The present invention relates to a passive method for obtaining target data from a sound source, preferably one which is moving, disposed in a nonsolid, or fluid medium, such as air or water, with the aid of a sound receiver which is remote from the sound source.
Target data are here understood to be parameters which indicate the state of the sound source, e.g. its distance, speed and possibly its position and/or type, e.g. the frequency spectrum radiated by the sound source.